David Cameron may struggle to secure his diplomatic objectives in Europe, after prominent politicians hit out at his recent anti-immigrant rhetoric.
Even traditional allies of the prime minister appear to be turning against him, as his comments against freedom of movement spark concern on the continent.
New German foreign minister Frank-Walter Steinmeier led the charge against Cameron, saying: "Germany has benefited tremendously from this and surely more than others.
"Now many young people from southern Europe are coming to us, to learn and study. That benefits us and also helps the states from which they come.
"Whoever questions that damages Europe and damages Germany."
The final comment associating Cameron with a threat to German interests will send a shiver up the spine of British diplomats, who have entered into tough negotiations with European allies ahead of a planned referendum on British membership of the EU in the coming years.
Cameron wants restrictions on freedom of movement for new EU members and a ban on benefits for up to two years.
His repeated reference to Polish immigrants when discussing the policy has already sparked a war of words between him and Polish premier Donald Tusk.
"Many times I have seen Englishmen behave, to put it delicately, reprehensibly in Krakow, Gdansk or Warsaw, but it never occurred to me use their loutish behaviour to smear everybody from Britain," Tusk commented.
Irish minister for Europe Paschal Donohoe told the Financial Times that Cameron was challenging a fundamental building block of the European project.
"The ability of people to move freely around the union is an absolute cornerstone of the European Union," he said.
"It represents an integral part of the deal overall that keeps the union together. [We have] freedom of people, freedom of services and freedom to move money around."
Another senior EU diplomat told the newspaper: "Weakening of European freedoms is out of question.
"One can only warn against sacrificing the great European achievements on the altar of political populism."
Cameron will find it hard to resist the issue of European freedom of movement after Ukip made it such a successful part of its political agenda.
With European elections now set to put him in third place, he is unlikely to relent on the rhetoric in the short-term.
Recent reports indicate the Tories want to come out with a new anti-immigration or anti-welfare policy every week until the general election.
Update: 14:15 GMT - Doubts have now been raised about the quote attributed to Steinmeier, which may have been taken out of context. More details about the questions around the original FT report can be found here.